There is a need for a tool for spreading soft malleable materials such as caulking or sealing materials. Such soft materials will sometimes be referred to herein as spreading materials. Such materials have typically been spread and smoothed with the finger. A purpose of using the spreading material is to seal a possible crack existing between two wall surfaces forming an inner corner. For example, the inner corner may be formed by a window frame mounted in a concrete wall opening. The spreading material should be applied and pressed against the walls evenly without leaving unwanted residues or an uneven surface on the sealing bead. Caulking tools have previously been proposed, for example in U.S. Pat. No. 3,267,516-Eckhaus and 3,744,079-Krause. A problem with such tools is that no effective way is provided to prevent escape of the spreading material around the tool, and this can result in unwanted residues and uneven sealing beads when the spreading material is spread.